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    <title>Document</title>
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    <script>
        var str = 'ajdfiajsjajsjaud'
        var obj = {}
        for( var i=0; i<str.length; i++ ){
            var code = str[i]
          
            if( obj[code]){
                obj[code]++
            }else{
                obj[code] = 1
            }
        }
       console.log(obj);
        var max = 0
        var k = ''
       for( key in obj){
         
           if( obj[key] > max){
               max = obj[key]
               k = key
           }
       }

       console.log( max , k );
       
       
    </script>
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